Chemical Properties
Ammonium formate, NH4HCO2, is the ammonium salt of formic acid. It is a colorless, hygroscopic, crystalline solid. It can be synthesized through treating ammonium carbonate with 85% formic acid. It is widely used in many organic reactions such as Leuckart reaction which is the reductive amination of aldehydes and ketones. It can also be used as a buffer in HPLC and LC/MS test. Moreover, it is also used in palladium on carbon (Pd/C) reduction of functional group. It can also be used for the preparation of formic acid in situ as well as being used to store formic acid.
Common HPLC Buffers: Ammonium formate (2.7<PH<3.7) does a fairly good job of filling the gap at the low-pH end.
Physical properties
White monoclinic deliquescent crystals or granules; density 1.280 g/cm
3; melts at 116°C; highly soluble in water (102 g/100 g at 0°C), solubility rapidly increasing with temperature (i.e., 531 g/100 g at 80°C); soluble in liquid ammonia, alcohol and ether.
Uses
Ammonium formate is widely used in various organic reactions like Leuckart reaction which involves the reductive amination of aldehydes and ketones. It serves as a buffer in high performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC/MS). It finds application in palladium on carbon (Pd/C) reduction of functional groups. For example, reduction of alkenes to alkanes and formaldehyde to methanol. It is also used to prepare formic acid insitu as well as used to store formic acid by making it as an ammonium salt.
Uses
Pure ammonium formate decomposes into formamide and water when heated, and this is its primary use in industry. Formic acid can also be obtained by reacting ammonium formate with a dilute acid, and since ammonium formate is also produced from formic acid, it can serve as a way of storing formic acid.
In chemical analysis, especially to ppt base metals from salts of the "noble" metals. Ammonium formate can also be used in palladium on carbon (Pd / C) reduction of functional groups. In the presence of Pd / C, ammonium formate decomposes to hydrogen, carbon dioxide, and ammonia.
Ammonium formate can be used for reductive amination of aldehydes and ketones (Leuckart reaction)
Ammonium formate can be used as a buffer in high performance liquid chromatography (HPLC), and is suitable for use with liquid chromatography/mass spectrometry (LC/MS). .
Definition
ChEBI: Ammonium formate is the ammonium salt of formic acid. It has a role as a buffer. It is functionally related to a formic acid.
Reactions
When heated, ammonium formate eliminates water, forming formamide. Upon further heating it forms to HCN and H
2O. A side reaction of this is the decomposition of formamide to CO and NH
3.
Air & Water Reactions
Ammonium formate is generally soluble in water.
Reactivity Profile
Salts, basic, such as Ammonium formate, are generally soluble in water. The resulting solutions contain moderate concentrations of hydroxide ions and have pH's greater than 7.0. They react as bases to neutralize acids. These neutralizations generate heat, but less or far less than is generated by neutralization of the bases in reactivity group 10 (Bases) and the neutralization of amines. They usually do not react as either oxidizing agents or reducing agents but such behavior is not impossible.
Health Hazard
Inhalation causes irritation of nose and throat. Ingestion irritates mouth and stomach. Contact with eyes or skin causes irritation.
Fire Hazard
Special Hazards of Combustion Products: Toxic and irritating ammonia and formic acid gases may form in fire.
Safety Profile
Moderately toxic by ingestion andintravenous routes. When heated to decomposition itemits toxic fumes of NOx and NH3.
Purification Methods
Heat the solid in NH3 vapour and dry it in a vacuum till the NH3 odour is faint (note that it can evaporate completely in a vacuum). Recrystallise it from absolute EtOH and then keep it in a desiccator over 99% H2SO4 in vacuo. It is very hygroscopic. It exists in two forms, stable needles and less stable plates. It also forms acid salts, i.e. HCO2NH4.3HCO2H and HCO2NH4.HCO2H. [Kensall & Adler J Am Chem Soc 43 1473 1921, Beilstein 2 IV 18.]
References
[1] http://www.orgsyn.org/demo.aspx?prep=CV2P0503
[2] https://www.alfa.com/zh-cn/catalog/014517/
[3] https://en.wikipedia.org/wiki/Ammonium_formate
[4] GAO X, MA Y, ZHOU F, et al. Promotion Mechanism of Ammonium Formate in Ammonium Salt Leaching Process for Weathered Crust Elution-Deposited Rare Earth Ores[J]. Minerals, 2023, 1 1: 0. DOI:10.3390/min13101286.
[5] A. S. KORNILOV. Uranium Stripping with Ammonium Acetate and Formate[J]. Radiochemistry, 2024, 65 1 supplement: S172-S176. DOI:10.1134/S1066362223070159.
[6] ISHANI BORTHAKUR, SABUJ KUNDU* Reductive Aminomethylation Using Ammonium Formate and Methanol as N1 and C1 Source: Direct Synthesis of Mono- and Di-Methylated Amines[J]. ACS Catalysis , 2024, 14 8: 5847-5857. DOI:
10.1021/acscatal.4c00346.
